3.2 FITB Practice

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Questions and Answers

B lymphocytes are the source of ______

antibodies

Cell mediated response refers to the direct involvement of ______ to attack an infection

cells

A humoral immune response involves direct contact between ______ and cytokines that bind to receptors on cell surfaces

cells, molecules

Macrophages encounter and process the antigen and display it on the cell surface with ______

MHC Signup and view all the answers

The B cell then becomes a ______ and releases antibodies

plasma cell Signup and view all the answers

Apixaban and Rivaroxaban are both highly selective, orally bioavailable, and reversible direct inhibitors of factor ______.

X Signup and view all the answers

Heparin accelerates antithrombin ______ activity 1000 fold.

III Signup and view all the answers

Dipyridamole is a platelet inhibitor that causes ______ and increases blood flow.

vasodilation Signup and view all the answers

The most toxic drug side-effect of anticoagulants is ______.

hemorrhage Signup and view all the answers

Warfarin sodium inhibits ______ K, which serves as a cofactor in the production of clotting factors II, VII, IX, and X.

Vitamin Signup and view all the answers

Fibrinolysis is the process where ______ lyses fibrin and degrades factors V and VIII, inhibiting further clotting.

plasmin Signup and view all the answers

Plasminogen activators include ______ plasminogen activator (t-PA) and urokinase.

tissue-type Signup and view all the answers

The clinical use of plasminogen activators includes treatment of ______ myocardial infarction.

acute Signup and view all the answers

The antifibrinolytic agent ______ competes with plasminogen and plasminogen activators for binding to fibrin.

e-aminocaproic acid (EACA) Signup and view all the answers

Anistreplase is a combination of ______ with an acylated plasminogen, which becomes deacylated in plasma.

streptokinase Signup and view all the answers

Study Notes

Types of White Blood Cells

Neutrophils: 50-70%, numerous short-lived phagocytes
Eosinophils: 1-5%, stain red, attack parasites
Basophils: 0.1%, stain blue, release histamine
Natural killer (NK) cells
Mast cells

Phagocytosis

Associated with Neutrophils, Monocytes, Macrophages
Enzymes in lysosome digest bacterium, triggering an inflammatory response
Phagocyte engulfs foreign particles or bacteria

Innate Immunity - Cell Mediated Immunity

Cytotoxic or Killer Cells (CD8 T cells) are activated by the release of IL-2 from T helper cells
CD8 cells recognize antigens on the surface of infected cells, attach to these cells, and secrete perforins
Perforins punch holes into infected cells, killing them

Innate Immunity - TLRs

Toll-Like Receptors (TLRs) are innate immune sensors
TLRs trigger a cascade of events to kill or protect against pathogens
They exist as transmembrane proteins, present on macrophages and a few other cells
They are conserved across vertebrates, very important part of innate immune system
They are sensitized to microbes (or their components)

Innate Immunity - Cytokines

Cytokines are small proteins, secreted by cells of the immune system
Examples include: Interferons, Interleukins, and Tumor Necrosis Factor (TNF)
They affect the behavior of other cells, are signalling molecules, and key players in both innate and acquired immunity
Cytokines are released by many cells of the immune system, including Neutrophils, Macrophages, Cytotoxic/Killer cells, and Lymphocytes

Innate Immunity - Interferon (IFN)

Signalling proteins produced by virus-infected monocytes and lymphocytes
Secreted proteins, key anti-viral proteins that inhibit protein synthesis
Warn neighboring cells that a virus is around, triggering fever, cell death, and increased antibody production

Innate Immunity - Complement

A large number of distinct plasma proteins that react with one another (C1-C9)
Complement can bind to microbes and coat the microbes, facilitating phagocytosis and cause lysis of pathogens
It is an essential part of innate immune response, enhancing the adaptive immune response

Innate Immunity - Inflammation

A complex biological process by which the body responds to injury
Macrophages release toxins (including reactive oxygen species or ROS) that injure tissues
Chronic inflammation is almost always accompanied by tissue damage

Adaptive (Acquired) Immunity

Immunity that develops after exposure, with the body remembering specific invader
It relies heavily on the production of antibodies
Passive or Active, Natural or Artificial

Humoral Immune Response

An immune response involving direct contact (cells, molecules bind to receptors on cell surfaces) and cytokines
Involves Antigen Presenting cells (APC), MHC, and the activation of B and T lymphocytes
Release of cytokines stimulates cells to get activated, multiply, and release antibodies

CO2 Transport and Buffering

CO2 is directly bound to Hemoglobin (at a site different from the one that binds Oxygen) in the blood.
The rest of the CO2 is converted into Bi-Carbonate ions and Hydrogen ions (H+) by the Enzyme Carbonic Anhydrase.
The reaction is reversible, proceeding to the right under conditions of lower temperature, higher pH, and increased oxygen pressure in the capillaries of the lungs.
Only about 5% of the CO2 generated in the tissues dissolves directly in the plasma.

Bohr Effect and Haldane Effect

The Bohr Effect: Hemoglobin releases oxygen in response to low pH, high temperature, and low oxygen pressure.
The Haldane Effect: Hemoglobin releases CO2 in response to high pH, low temperature, and high oxygen pressure.

The Cardiovascular System and CO2

CO2 is an acid, and its accumulation can lead to a drop in blood pH.
The equation CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3− shows the conversion of CO2 into H+ and HCO3−.

Blood Clotting and Hemostasis

Blood clotting has several positive feedback loops that amplify the clotting process.
The TF-VII complex starts the clotting process, which activates Factor IX and X, leading to the formation of thrombin.
Thrombin activates more Factors V, VIII, and XI, and also converts fibrinogen to fibrin.
Platelets release thromboxane A2, which recruits and activates more platelets, and serotonin, which enhances their clumping and promotes blood vessel constriction.

Anticoagulants and Thrombocytopathics

Direct-acting anticoagulants: Apixaban (Eliquis) and Rivaroxaban (Xarelto) are highly selective, orally bioavailable, and reversible direct inhibitors of factor X.
Heparin: accelerates antithrombin III activity, which inactivates factors IX, X, and XI, and thrombin, preventing fibrin formation.
Indirect-acting anticoagulants: Dicumarol or Warfarin sodium inhibits Vitamin K, which is necessary for the production of clotting factors II, VII, IX, and X.
Platelet inhibitors (Thrombocytopathics): Aspirin inhibits thromboxane synthesis, resulting in decreased platelet aggregation, and dipyridamole causes vasodilation and increases blood flow, while inhibiting phosphodiesterase, resulting in reduced platelet aggregation.

Erythrocytes (RBCs)

Males have approximately 5.4 million Erythrocytes per cubic millimeter of blood (range: 4.6 - 6.2 million), while females have about 4.8 million (range: 4.2 - 5.4 million).
Males have approximately 10% more Erythrocytes than females.
Normal Erythrocytes are biconcave disks about 7.5 micrometers in diameter with thicker edges than the center of the cell.
The biconcave shape increases the surface area of the erythrocyte, making the movement of gases (oxygen and carbon dioxide) into and out of the cell more rapid.
The erythrocyte can bend or fold around its thin center, decreasing its size and enabling it to pass more easily through small blood vessels.

RBC Factoids

Women average about 4.8 million RBCs per cubic millimeter (mm3) of blood, while men average about 5.4 x 10^6 per µl.
These values can vary depending on factors such as health and altitude.
Peruvians living at 18,000 feet may have as many as 8.3 x 10^6 RBCs per µl.

RBC Development and Function

RBC precursors mature in the bone marrow closely attached to a macrophage.
They manufacture hemoglobin until it accounts for about 90% of the dry weight of the cell.
The nucleus is squeezed out of the cell and is ingested by the macrophage.
No longer needed proteins are expelled from the cell in vesicles called exosomes.
RBCs are terminally differentiated, meaning they can never divide.
They live about 120 days and then are ingested by phagocytic cells in the liver and spleen.
Most of the iron in their hemoglobin is reclaimed for reuse.

Carbon Dioxide Transport

About one-half of the CO2 is directly bound to hemoglobin (at a site different from the one that binds oxygen).
The rest is converted into bicarbonate ions and hydrogen ions by the enzyme carbonic anhydrase.
Bicarbonate ions diffuse back out into the plasma, while hydrogen ions bind to the protein portion of the hemoglobin.

Hemoglobin and Oxygen

Under the conditions of lower temperature, higher pH, and increased oxygen pressure in the capillaries of the lungs, the reaction proceeds to the right, and deoxygenated hemoglobin becomes oxyhemoglobin.
Under the conditions of higher temperature, lower pH, and lower oxygen pressure in the tissues, the reverse reaction is promoted, and oxyhemoglobin gives up its oxygen.

The Cardiovascular System

The cardiovascular system distributes nutrients, oxygen, and hormones to all cells in the body and carries away metabolic waste products.
The system consists of the heart, blood, arteries, arterioles, venules, and capillaries.

Blood

Blood is composed of plasma and formed elements.
Plasma makes up about 55% of the total blood volume and is composed of 92% water, electrolytes, and proteins.
Formed elements include blood cells and platelets.
Blood cells are divided into red blood cells (RBCs), which make up about 99.9% of all blood cells, and white blood cells (WBCs), which make up about 0.1% of all blood cells.
RBCs have no nucleus and are biconcave in shape, with 95% of their composition made up of hemoglobin (Hb).
Hb can reversibly bind 4O2 and 4CO2.

Platelets

Platelets have no nucleus and are involved in blood clotting.
They engulf and destroy pathogens, induce inflammation, and fight parasitic infections.
Platelets produce antibodies and provide immunity.

Blood Clotting

Hemostasis is the process of stopping bleeding, which involves platelet activation, clotting, and fibrinolysis.
Platelets adhere to collagen in the damaged blood vessel wall, releasing thromboxane A2, which recruits and activates more platelets.
The clotting process involves a series of coagulation factors, including thrombin, factor VII, and factor IX.
Fibrinolysis is the process of breaking down the clot, which involves the conversion of plasminogen to plasmin by plasminogen activators.

Fibrinolysis

Plasmin is generated from the enzymatic conversion of plasminogen.
Plasmin lyses fibrin, degrades factors V and VIII, and inhibits further clotting.
Plasminogen activators, such as tissue-type plasminogen activator (t-PA) and urokinase, convert plasminogen to plasmin.
Antifibrinolytics, such as e-aminocaproic acid (EACA) and alpha2-antiplasmin, can be used to limit fibrinolytic activity.

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This quiz covers different types of immune cells, their functions, and percentages in the human body. Learn about neutrophils, T-lymphocytes, eosinophils, basophils, natural killer cells, and mast cells.